/*
 *  Copyright 2008-2018 NVIDIA Corporation
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

/*! \file host_vector.h
 *  \brief A dynamically-sizable array of elements which resides in memory
 *         accessible to hosts.
 */

#pragma once

#include <thrust/detail/config.h>

#if defined(_CCCL_IMPLICIT_SYSTEM_HEADER_GCC)
#  pragma GCC system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_CLANG)
#  pragma clang system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_MSVC)
#  pragma system_header
#endif // no system header
#include <thrust/detail/memory_wrapper.h>
#include <thrust/detail/vector_base.h>

#include <cuda/std/initializer_list>
#include <cuda/std/utility>

#include <vector>

THRUST_NAMESPACE_BEGIN

/*! \addtogroup container_classes Container Classes
 *  \addtogroup host_containers Host Containers
 *  \ingroup container_classes
 *  \{
 */

/*! A \p host_vector is a container that supports random access to elements,
 *  constant time removal of elements at the end, and linear time insertion
 *  and removal of elements at the beginning or in the middle. The number of
 *  elements in a \p host_vector may vary dynamically; memory management is
 *  automatic. The memory associated with a \p host_vector resides in memory
 *  accessible to hosts.
 *
 *  \see https://en.cppreference.com/w/cpp/container/vector
 *  \see device_vector
 *  \see universal_vector
 */
template <typename T, typename Alloc = std::allocator<T>>
class host_vector : public detail::vector_base<T, Alloc>
{
private:
  using Parent = detail::vector_base<T, Alloc>;

public:
  /*! \cond
   */
  using size_type  = typename Parent::size_type;
  using value_type = typename Parent::value_type;
  /*! \endcond
   */

  /*! This constructor creates an empty \p host_vector.
   */
  _CCCL_HOST host_vector()
      : Parent()
  {}

  /*! This constructor creates an empty \p host_vector.
   *  \param alloc The allocator to use by this host_vector.
   */
  _CCCL_HOST host_vector(const Alloc& alloc)
      : Parent(alloc)
  {}

  /*! The destructor erases the elements.
   */
  //  Define an empty destructor to explicitly specify
  //  its execution space qualifier, as a workaround for nvcc warning
  _CCCL_HOST ~host_vector() {}

  /*! This constructor creates a \p host_vector with the given
   *  size.
   *  \param n The number of elements to initially create.
   */
  _CCCL_HOST explicit host_vector(size_type n)
      : Parent(n)
  {}

  //! This constructor creates a \p host_vector with the given size, performing only default-initialization instead of
  //! value-initialization.
  //! \param n The number of elements to initially create.
  _CCCL_HOST host_vector(size_type n, default_init_t)
      : Parent(n, default_init_t{})
  {}

  //! This constructor creates a \p host_vector with the given size, without initializing elements. It mandates that
  //! the element type is trivially default-constructible.
  //! \param n The number of elements to initially create.
  _CCCL_HOST host_vector(size_type n, no_init_t)
      : Parent(n, no_init_t{})
  {}

  /*! This constructor creates a \p host_vector with the given
   *  size.
   *  \param n The number of elements to initially create.
   *  \param alloc The allocator to use by this host_vector.
   */
  _CCCL_HOST explicit host_vector(size_type n, const Alloc& alloc)
      : Parent(n, alloc)
  {}

  /*! This constructor creates a \p host_vector with copies
   *  of an exemplar element.
   *  \param n The number of elements to initially create.
   *  \param value An element to copy.
   */
  _CCCL_HOST explicit host_vector(size_type n, const value_type& value)
      : Parent(n, value)
  {}

  /*! This constructor creates a \p host_vector with copies
   *  of an exemplar element.
   *  \param n The number of elements to initially create.
   *  \param value An element to copy.
   *  \param alloc The allocator to use by this host_vector.
   */
  _CCCL_HOST explicit host_vector(size_type n, const value_type& value, const Alloc& alloc)
      : Parent(n, value, alloc)
  {}

  /*! Copy constructor copies from an exemplar \p host_vector.
   *  \param v The \p host_vector to copy.
   */
  _CCCL_HOST host_vector(const host_vector& v)
      : Parent(v)
  {}

  /*! Copy constructor copies from an exemplar \p host_vector.
   *  \param v The \p host_vector to copy.
   *  \param alloc The allocator to use by this host_vector.
   */
  _CCCL_HOST host_vector(const host_vector& v, const Alloc& alloc)
      : Parent(v, alloc)
  {}

  /*! Move constructor moves from another host_vector.
   *  \param v The host_vector to move.
   */
  _CCCL_HOST host_vector(host_vector&& v)
      : Parent(::cuda::std::move(v))
  {}

  /*! Move constructor moves from another host_vector.
   *  \param v The host_vector to move.
   *  \param alloc The allocator to use by this host_vector.
   */
  _CCCL_HOST host_vector(host_vector&& v, const Alloc& alloc)
      : Parent(::cuda::std::move(v), alloc)
  {}

  /*! Assign operator copies from an exemplar \p host_vector.
   *  \param v The \p host_vector to copy.
   */
  _CCCL_HOST host_vector& operator=(const host_vector& v)
  {
    Parent::operator=(v);
    return *this;
  }

  /*! Move assign operator moves from another host_vector.
   *  \param v The host_vector to move.
   */
  _CCCL_HOST host_vector& operator=(host_vector&& v)
  {
    Parent::operator=(::cuda::std::move(v));
    return *this;
  }

  /*! Copy constructor copies from an exemplar \p host_vector with different type.
   *  \param v The \p host_vector to copy.
   */
  template <typename OtherT, typename OtherAlloc>
  _CCCL_HOST host_vector(const host_vector<OtherT, OtherAlloc>& v)
      : Parent(v)
  {}

  /*! Assign operator copies from an exemplar \p host_vector with different type.
   *  \param v The \p host_vector to copy.
   */
  template <typename OtherT, typename OtherAlloc>
  _CCCL_HOST host_vector& operator=(const host_vector<OtherT, OtherAlloc>& v)
  {
    Parent::operator=(v);
    return *this;
  }

  /*! Copy constructor copies from an exemplar <tt>std::vector</tt>.
   *  \param v The <tt>std::vector</tt> to copy.
   */
  template <typename OtherT, typename OtherAlloc>
  _CCCL_HOST host_vector(const std::vector<OtherT, OtherAlloc>& v)
      : Parent(v)
  {}

  /*! Assign operator copies from an exemplar <tt>std::vector</tt>.
   *  \param v The <tt>std::vector</tt> to copy.
   */
  template <typename OtherT, typename OtherAlloc>
  _CCCL_HOST host_vector& operator=(const std::vector<OtherT, OtherAlloc>& v)
  {
    Parent::operator=(v);
    return *this;
  }

  /*! Copy construct from a \p vector_base whose element type is convertible
   *  to \c T.
   *
   *  \param v The \p vector_base to copy.
   */
  template <typename OtherT, typename OtherAlloc>
  _CCCL_HOST host_vector(const detail::vector_base<OtherT, OtherAlloc>& v)
      : Parent(v)
  {}

  /*! Assign a \p vector_base whose element type is convertible to \c T.
   *
   *  \param v The \p vector_base to copy.
   */
  template <typename OtherT, typename OtherAlloc>
  _CCCL_HOST host_vector& operator=(const detail::vector_base<OtherT, OtherAlloc>& v)
  {
    Parent::operator=(v);
    return *this;
  }

  /*! This constructor builds a \p host_vector from an intializer_list.
   *  \param il The intializer_list.
   */
  host_vector(::cuda::std::initializer_list<T> il)
      : Parent(il)
  {}

  /*! This constructor builds a \p host_vector from an intializer_list.
   *  \param il The intializer_list.
   *  \param alloc The allocator to use by this host_vector.
   */
  host_vector(::cuda::std::initializer_list<T> il, const Alloc& alloc)
      : Parent(il, alloc)
  {}

  /*! Assign an \p intializer_list with a matching element type
   *  \param il The intializer_list.
   */
  host_vector& operator=(::cuda::std::initializer_list<T> il)
  {
    Parent::operator=(il);
    return *this;
  }

  /*! This constructor builds a \p host_vector from a range.
   *  \param first The beginning of the range.
   *  \param last The end of the range.
   */
  template <typename InputIterator>
  _CCCL_HOST host_vector(InputIterator first, InputIterator last)
      : Parent(first, last)
  {}

  /*! This constructor builds a \p host_vector from a range.
   *  \param first The beginning of the range.
   *  \param last The end of the range.
   *  \param alloc The allocator to use by this host_vector.
   */
  template <typename InputIterator>
  _CCCL_HOST host_vector(InputIterator first, InputIterator last, const Alloc& alloc)
      : Parent(first, last, alloc)
  {}

// declare these members for the purpose of Doxygenating them
// they actually exist in a base class
#if 0
    /*! \brief Resizes this vector to the specified number of elements.
     *  \param new_size Number of elements this vector should contain.
     *  \param x Data with which new elements should be populated.
     *  \throw std::length_error If n exceeds max_size().
     *
     *  This method will resize this vector to the specified number of
     *  elements.  If the number is smaller than this vector's current
     *  size this vector is truncated, otherwise this vector is
     *  extended and new elements are populated with given data.
     */
    void resize(size_type new_size, const value_type &x = value_type());

    //! \brief Resizes this vector to the specified number of elements, performing default-initialization instead of
    //!         value-initialization.
    //! \param new_size Number of elements this vector should contain.
    //! \throw std::length_error If n exceeds max_size().
    void resize(size_type new_size, default_init_t);

    //! \brief Resizes this vector to the specified number of elements, without initializing elements. It mandates
    //! that the element type is trivially default-constructible.
    //! \param new_size Number of elements this vector should contain.
    //! \throw std::length_error If n exceeds max_size().
    void resize(size_type new_size, no_init_t);

    /*! Returns the number of elements in this vector.
     */
    size_type size() const;

    /*! Returns the size() of the largest possible vector.
     *  \return The largest possible return value of size().
     */
    size_type max_size() const;

    /*! \brief If n is less than or equal to capacity(), this call has no effect.
     *         Otherwise, this method is a request for allocation of additional memory. If
     *         the request is successful, then capacity() is greater than or equal to
     *         n; otherwise, capacity() is unchanged. In either case, size() is unchanged.
     *  \throw std::length_error If n exceeds max_size().
     */
    void reserve(size_type n);

    /*! Returns the number of elements which have been reserved in this
     *  vector.
     */
    size_type capacity() const;

    /*! This method shrinks the capacity of this vector to exactly
     *  fit its elements.
     */
    void shrink_to_fit();

    /*! \brief Subscript access to the data contained in this vector_dev.
     *  \param n The index of the element for which data should be accessed.
     *  \return Read/write reference to data.
     *
     *  This operator allows for easy, array-style, data access.
     *  Note that data access with this operator is unchecked and
     *  out_of_range lookups are not defined.
     */
    reference operator[](size_type n);

    /*! \brief Subscript read access to the data contained in this vector_dev.
     *  \param n The index of the element for which data should be accessed.
     *  \return Read reference to data.
     *
     *  This operator allows for easy, array-style, data access.
     *  Note that data access with this operator is unchecked and
     *  out_of_range lookups are not defined.
     */
    const_reference operator[](size_type n) const;

    /*! This method returns an iterator pointing to the beginning of
     *  this vector.
     *  \return mStart
     */
    iterator begin();

    /*! This method returns a const_iterator pointing to the beginning
     *  of this vector.
     *  \return mStart
     */
    const_iterator begin() const;

    /*! This method returns a const_iterator pointing to the beginning
     *  of this vector.
     *  \return mStart
     */
    const_iterator cbegin() const;

    /*! This method returns a reverse_iterator pointing to the beginning of
     *  this vector's reversed sequence.
     *  \return A reverse_iterator pointing to the beginning of this
     *          vector's reversed sequence.
     */
    reverse_iterator rbegin();

    /*! This method returns a const_reverse_iterator pointing to the beginning of
     *  this vector's reversed sequence.
     *  \return A const_reverse_iterator pointing to the beginning of this
     *          vector's reversed sequence.
     */
    const_reverse_iterator rbegin() const;

    /*! This method returns a const_reverse_iterator pointing to the beginning of
     *  this vector's reversed sequence.
     *  \return A const_reverse_iterator pointing to the beginning of this
     *          vector's reversed sequence.
     */
    const_reverse_iterator crbegin() const;

    /*! This method returns an iterator pointing to one element past the
     *  last of this vector.
     *  \return begin() + size().
     */
    iterator end();

    /*! This method returns a const_iterator pointing to one element past the
     *  last of this vector.
     *  \return begin() + size().
     */
    const_iterator end() const;

    /*! This method returns a const_iterator pointing to one element past the
     *  last of this vector.
     *  \return begin() + size().
     */
    const_iterator cend() const;

    /*! This method returns a reverse_iterator pointing to one element past the
     *  last of this vector's reversed sequence.
     *  \return rbegin() + size().
     */
    reverse_iterator rend();

    /*! This method returns a const_reverse_iterator pointing to one element past the
     *  last of this vector's reversed sequence.
     *  \return rbegin() + size().
     */
    const_reverse_iterator rend() const;

    /*! This method returns a const_reverse_iterator pointing to one element past the
     *  last of this vector's reversed sequence.
     *  \return rbegin() + size().
     */
    const_reverse_iterator crend() const;

    /*! This method returns a const_reference referring to the first element of this
     *  vector.
     *  \return The first element of this vector.
     */
    const_reference front() const;

    /*! This method returns a reference pointing to the first element of this
     *  vector.
     *  \return The first element of this vector.
     */
    reference front();

    /*! This method returns a const reference pointing to the last element of
     *  this vector.
     *  \return The last element of this vector.
     */
    const_reference back() const;

    /*! This method returns a reference referring to the last element of
     *  this vector_dev.
     *  \return The last element of this vector.
     */
    reference back();

    /*! This method returns a pointer to this vector's first element.
     *  \return A pointer to the first element of this vector.
     */
    pointer data();

    /*! This method returns a const_pointer to this vector's first element.
     *  \return a const_pointer to the first element of this vector.
     */
    const_pointer data() const;

    /*! This method resizes this vector to 0.
     */
    void clear();

    /*! This method returns true iff size() == 0.
     *  \return true if size() == 0; false, otherwise.
     */
    bool empty() const;

    /*! This method appends the given element to the end of this vector.
     *  \param x The element to append.
     */
    void push_back(const value_type &x);

    /*! This method erases the last element of this vector, invalidating
     *  all iterators and references to it.
     */
    void pop_back();

    /*! This method swaps the contents of this host_vector with another vector.
     *  \param v The vector with which to swap.
     */
    void swap(host_vector &v);

    /*! This method removes the element at position pos.
     *  \param pos The position of the element of interest.
     *  \return An iterator pointing to the new location of the element that followed the element
     *          at position pos.
     */
    iterator erase(iterator pos);

    /*! This method removes the range of elements [first,last) from this vector.
     *  \param first The beginning of the range of elements to remove.
     *  \param last The end of the range of elements to remove.
     *  \return An iterator pointing to the new location of the element that followed the last
     *          element in the sequence [first,last).
     */
    iterator erase(iterator first, iterator last);

    /*! This method inserts a single copy of a given exemplar value at the
     *  specified position in this vector.
     *  \param position The insertion position.
     *  \param x The exemplar element to copy & insert.
     *  \return An iterator pointing to the newly inserted element.
     */
    iterator insert(iterator position, const T &x);

    /*! This method inserts a copy of an exemplar value to a range at the
     *  specified position in this vector.
     *  \param position The insertion position
     *  \param n The number of insertions to perform.
     *  \param x The value to replicate and insert.
     */
    void insert(iterator position, size_type n, const T &x);

    /*! This method inserts a copy of an input range at the specified position
     *  in this vector.
     *  \param position The insertion position.
     *  \param first The beginning of the range to copy.
     *  \param last  The end of the range to copy.
     *
     *  \tparam InputIterator is a model of <a href="https://en.cppreference.com/w/cpp/iterator/input_iterator>Input Iterator</a>,
     *                        and \p InputIterator's \c value_type is a model of <a href="https://en.cppreference.com/w/cpp/named_req/CopyAssignable">Assignable</a>.
     */
    template<typename InputIterator>
    void insert(iterator position, InputIterator first, InputIterator last);

    /*! This version of \p assign replicates a given exemplar
     *  \p n times into this vector.
     *  \param n The number of times to copy \p x.
     *  \param x The exemplar element to replicate.
     */
    void assign(size_type n, const T &x);

    /*! This version of \p assign makes this vector a copy of a given input range.
     *  \param first The beginning of the range to copy.
     *  \param last  The end of the range to copy.
     *
     *  \tparam InputIterator is a model of <a href="https://en.cppreference.com/w/cpp/named_req/InputIterator">Input Iterator</a>.
     */
    template<typename InputIterator>
    void assign(InputIterator first, InputIterator last);

    /*! This method returns a copy of this vector's allocator.
     *  \return A copy of the allocator used by this vector.
     */
    allocator_type get_allocator() const;
#endif // end doxygen-only members

  /*! Exchanges the values of two vectors.
   *  \p x The first \p host_vector of interest.
   *  \p y The second \p host_vector of interest.
   */
  friend void swap(host_vector& a, host_vector& b) noexcept(noexcept(a.swap(b)))
  {
    a.swap(b);
  }
};

/*! \}
 */

THRUST_NAMESPACE_END
